Liwei Lin (Advisor)

We present an area- and power-efficient application-specific integrated circuit (ASIC) for a miniaturized 3-D ultrasound system. The ASIC is designed to transmit pulse and receive echo through a 36-channel 2-D piezoelectric Micromachined Ultrasound Transducer (pMUT) array. The 36-channel ASIC integrates a transmitter (TX), a receiver (RX), and an analog-to-digital converter (ADC) within the 250-μm pitch channel while consuming low-power and supporting calibration to compensate for the process variation of the pMUT. The charge-recycling high-voltage TX (CRHV-TX) in standard CMOS...

This work presents the sense of touch via non-contact ultrasonic waves by a dual-electrode bimorph piezoelectric micromachined transducer (pMUT) array. The prototype device has 12×12 elements with circular diaphragms of 415μm in radius made of 2μm-thick AlN. They are fabricated by a CMOS compatible micromachining process resulting a resonant frequency at 109.4kHz. Experimentally, a best haptic sensation on human fingers is found when emitting high frequency ultrasonic waves to emulate 100Hz signals by means of pulse width modulation with a 50% duty cycle. Strong haptic sensations are...

This paper reports the approach to boost the acoustic performances of PMUTs (Piezoelectric Micromachined Ultrasonic Transducers) including vibrational amplitude, acoustic pressure and electromechanical coupling by using the pinning boundary structure. An analytical model is developed based on an assumed mode shape and is validated with matching results from numerical simulations. Prototyped devices are fabricated and tested with a measured 2.5X improvement in displacement and 3.5X higher pressure output per volt at resonance as compared to those of PMUTs with clamped boundary. As a...

We present a new way for the fabrication of stretchable electronics systems without photolithography procedures by exploiting the through-cut, tunnel-cut, and blind-cut modes of a commercial desktop-size vinyl cutter. Compared to previous studies involving photolithography, our method produces a batch of representative devices in significantly reduced time (by ~69%) and cost (by ~73%) with similar feature sizes (100-1000um). Our inclusion of blind-cut and tunnel- cut modes facilitates the fabrication of complex stretchable electronics systems, rather than only electrodes and...